#include <iostream>
#include <queue>

using namespace std;



void test1() {
	queue<int> q;

	q.push(1);
	q.push(2);

	cout << "size:" << q.size() << endl;
	cout << "empty:" << q.empty() << endl;
	cout << "front:" << q.front() << endl;
	cout << "back:" << q.back() << endl;

	q.emplace(3);
	cout << "emplace back:" << q.back() << endl;
	q.pop();
	cout << "pop back:" << q.front() << endl;
}


int main() {

	test1();

	return 0;
}